This invention relates to a composition of antimicrobial agents. In a particular aspect this invention relates to an antimicrobial composition useful for controlling the growth of microorganisms.
One of the problems in metalworking industries is the susceptibility of metalworking fluids (which are emulsions of oil or chemical lubricants in water) to microbial attack. Were it not for this microbial contamination, the oil could be used for many months, but actually the microbial growth shortens the working life of the oil considerably. Microbial action may cause the emulsion to break and become acidic, thus causing corrosion problems. Some of the microbes may be pathogenic which can cause skin infections and other industrial health problems. In addition the microbial mycelia can clog pumps and valves, and often a foul odor develops. In a large installation, frequent replacement of metalworking fluids is costly.
Tris(hydroxymethyl)nitromethane has long been used for antimicrobial purposes, e.g. in metalworking fluids. Its effectiveness for this use was described by H. O. Wheeler and E. O. Bennett, Applied Microbiology 4, 122-126 (1956); and E. O. Bennett, Soap and Chemical Specialties 32, 47-49 (October 1956); 46-48 (November 1956). The product has been particularly useful in preserving aqueous media such as cutting oils, latex paint, recirculated cooling water, etc. However it lacks long term stability under some conditions of use and additional amounts must be added periodically in long term applications.
The mixture of 4-(2-nitrobutyl)morpholine and 4,4-(2-ethyl-2-nitrotrimethylene)dimorpholine has also been long known for its antimicrobial properties. It is available commercially as Bioban .RTM. P-1487 from IMC Chemical Group, Inc. Hereinafter this mixture will be referred to as P-1487. P-1487 is a highly effective antimicrobial and is advantageous over tris(hydroxymethyl)nitromethane in that it is quite stable under use conditions. However it is expensive by comparison to the latter, which is quite low cost.